2025

abstract

english

EN Methylcellulose (MC, E461), a water-soluble polymer, and lecithin (LS), a natural phospholipid, are commonly used to improve the viscosity and stability of emulsions. Lecithin is included in the surfactant group, has a low molecular weight and is a polar compound. Methylcellulose is a derivative of cellulose, which has been chemically modified to have the expected rheological properties. It is used to stabilize emulsions, as it extends the shelf life of emulsions, and also as a thickening agent [1]. In hot water, its viscosity increases, so it turns into a gel. For this reason, it has found its use in many industries, for example, in the food industry as an emulsifying ingredient and mayonnaise stabilizer and in the cosmetics industry, in creams or pharmaceuticals in tablets. The purpose of this study is to analyse the rheological properties and stability of emulsions containing a mixture of methylcellulose and lecithin. Methylcellulose at 1% and lecithin at concentrations of 1, 3 and 5% wt. were used to make the emulsion. The concentration of the dispersed phase was 30 vol% (the viscosities of the oils at 20 ̊C are: rapeseed oil: 0.072 (Pa∙s), linseed oil: 0.047 (Pa∙s) and corn oil: 0.0325 (Pa∙s)). The equipment used was: Lamy RM-100 plus rheometer, Anton Paar Physica MCR 501 rheometer to plot viscosity and flow curves. The optical micrographs of the emulsions were captured by a Nikon Eclipse 50i microscope (Tokyo, Japan). The IKA T18 digital ULTRA TURRAX homogenizer was used to disperse linseed, rapeseed and corn oils in the samples. The stability of the emulsions was analyzed by observing their samples placed in transparent containers over time. The results of rheological tests indicate that the emulsions studied belong to shear-thinning fluids with viscoelastic properties. The viscosity of the emulsion increases with the increase of lecithin content in the continuous phase. Higher LS concentrations also increase the stability of the emulsions, which do not show any visual signs of instability, e.g. phase separation, even after two weeks of preparation. It has been demonstrated that the addition of lecithin to the hydrocolloid solution results in the formation of a stable emulsion with very small droplets. This leads to an increase in emulsion viscosity, particularly at low shear rates. The emulsions developed in this study have the potential for use in cosmetic formulations and as drug carriers, owing to their biocompatibility and environmental sustainability.

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1st International Conference PUT STEM Day 2025: book of abstracts

1st International Conference PUT STEM Day 2025 : Science Technology Engineering Mathematics, 10.01.2025, Poznań, Polska